Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_PASS,T_MIXED_ES autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DA42FC65BAE for ; Fri, 14 Dec 2018 02:32:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9264720879 for ; Fri, 14 Dec 2018 02:32:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Tt/SgTj/" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9264720879 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-bluetooth-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728987AbeLNCcm (ORCPT ); Thu, 13 Dec 2018 21:32:42 -0500 Received: from mail-ot1-f48.google.com ([209.85.210.48]:38995 "EHLO mail-ot1-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728779AbeLNCcl (ORCPT ); Thu, 13 Dec 2018 21:32:41 -0500 Received: by mail-ot1-f48.google.com with SMTP id n8so4028728otl.6 for ; Thu, 13 Dec 2018 18:32:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=EMoUWBm6fZvqNkIGcw79HLXyUQvjlMafEQM6E2nEeJQ=; b=Tt/SgTj/dWOek8Kgg/lm/3vj5pJZ9Q1DaL7XtqslVU6NNQ9S/XFuxjYS8ec7JonZBZ 5dMp6igS3D1fxK1SdJ+8lF9TZUNVIXfLVnggTqJVtzLHShgQ3/qKOxnQ4WfhRWykw8Ut 0c9TxIFI0hU/WLl2+EDbAMgTiKkIkCxy9TvjakPuvwfMRAe5OtawOgMgduRT8mS6QUOa c77z6hR47uINYXeiArXvfeEIqaOVIc72c57gouae8L4UB20ep3XlwTK8tqJoAj6xGxtA Q60zp3JURqFRjgOTNNFHQd19JjLU/Cgx01yshpz/gCSezSQH+v3i2GxGhGysJntV1D7O qd4w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=EMoUWBm6fZvqNkIGcw79HLXyUQvjlMafEQM6E2nEeJQ=; b=rLP+kFCG3qqSc2gNK7TLwqbAVTQ4Q7+9ZJaeHeEu/Bzzm1+cyIH7JWCMo7LrTcUyoP UZ4yjHVCkR9483mo6CFVc460armxHnQIOeap51XYEETY/CvV+poqkpf/z7/ILFjs0im2 k4pX76BqjIqDDejBggicZmSpo1+eiZG/qlf+cSycsAWscRZSzAXAjl+z/TCrXdF3HT1v aiRKXFf6V+pu3BI9HhJH4PiZiAqGnWmzd9AbiJIhDeRrzq3fald5S5g/cdlv1TD3V/4l MEKWwwyJN7mXmwwzAA2uAYGpkqguWsLF5qlmfp5nURzotYtqtWKmj+x26AyDw+Zri/d2 fMCw== X-Gm-Message-State: AA+aEWZLtSa8kg/iIWOkH19DIujrPah4W8nz7J0FZf0EluXnyY6U3phl i5Ys8llOyou7h+hcjJG67XUFARhUMA57RKkKcF4= X-Google-Smtp-Source: AFSGD/UFhGgTbclzgafMuelX3JGrkKkKkRmmjzFTj1jLkk5GcCwt+gwkMSwUPvdw1KLQm96jyHdZsJBMGIkA5kn4G68= X-Received: by 2002:a05:6830:1004:: with SMTP id a4mr871349otp.254.1544754760063; Thu, 13 Dec 2018 18:32:40 -0800 (PST) MIME-Version: 1.0 References: In-Reply-To: From: Luiz Augusto von Dentz Date: Fri, 14 Dec 2018 04:32:26 +0200 Message-ID: Subject: Re: BLE advertisement re-enabling after ble connection goes away To: Yunhan Wang Cc: mturon@google.com, Marcel Holtmann , "linux-bluetooth@vger.kernel.org" Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Sender: linux-bluetooth-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-bluetooth@vger.kernel.org Hi Yunhan, On Fri, Dec 14, 2018 at 4:06 AM Yunhan Wang wrote: > > Hi, Luiz > > Thanks for your reply. A little bit confused here. > > There is no code in bluez that directly re-enable advertisement, if > there is, could you show the code location in bluez? Isn't that what the following code does: https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth.git/tre= e/net/bluetooth/hci_request.c#n1386 > Bluetooth in kernel is responsible for re-enabling advertisement? The > responsibility for re-enabling the advertising is kernel instead of > bluez and user application code. Yes it is the kernel which re-enables it and it has been doing this for a long while so I wonder why all of the a sudden we are discussing about it. Is there a bug related to it? > Thanks > Best wishes > Yunhan > > > > On Thu, Dec 13, 2018 at 5:21 PM Luiz Augusto von Dentz > wrote: > > > > Hi Yunhan, > > > > You already answered your question, it is reenabled by > > hci_req_reenable_advertising > > > > > > On Fri, Dec 14, 2018 at 1:13 AM Yunhan Wang wrot= e: > > > > > > Hi, Luiz > > > > > > Rephrasing a little bit.. > > > > > > From what you describes, it seems Bluez is taking the responsibility > > > to reenable the advertisement in peripheral side after the previous > > > ble connection goes > > > away. > > > > > > When I did local test, the ble peripheral is using bluez, I create > > > gatt server and ble advertisment using Bluez DBus API, when remote > > > connection in central disconnects, I see kernel in Bluez in periphera= l > > > side do receive > > > HCI_EV_DISCONN_COMPLETE event, and trigger > > > hci_req_reenable_advertising. > > > > > > Maybe you can share the code location where Bluez is reenabling the > > > advertisement after ble connection goes away? > > > > > > Thanks > > > Best wishes > > > On Thu, Dec 13, 2018 at 3:10 PM Yunhan Wang wr= ote: > > > > > > > > Hi, Luiz > > > > > > > > From what you describes, it seems Bluez is taking the responsibilit= y > > > > to reenable the advertisement after the previous ble connection goe= s > > > > away. > > > > > > > > When I did local test, the ble peripheral is using bluez, I create > > > > gatt server and ble advertisment using Bluez DBus API, when remote > > > > connection in central disconnects, I see kernel in Bluez do receive > > > > HCI_EV_DISCONN_COMPLETE event, and trigger > > > > hci_req_reenable_advertising. > > > > > > > > Maybe you can share the code location where Bluez is reenabling the > > > > advertisement after ble connection goes away? > > > > > > > > Thanks > > > > Best wishes > > > > Yunhan > > > > > > > > On Thu, Dec 13, 2018 at 2:30 PM Martin Turon wr= ote: > > > > > > > > > > Hi Luiz, > > > > > > > > > > Is this behavior also expected on raw hci sockets? Because my ob= servation is that when working with raw hci over such sockets, auto-reenabl= e does not occur. > > > > > > > > > > #define BTPROTO_HCI 1 > > > > > #define HCI_CHANNEL_USER 1 > > > > > > > > > > struct sockaddr_hci shci; > > > > > shci.hci_family =3D AF_BLUETOOTH; > > > > > shci.hci_dev =3D s_ble_hci_device; > > > > > shci.hci_channel =3D HCI_CHANNEL_USER; > > > > > > > > > > s =3D socket(PF_BLUETOOTH, SOCK_RAW, BTPROTO_HCI); > > > > > rc =3D bind(s, (struct sockaddr *)&shci, sizeof(shci)); > > > > Raw socket commands might actually work but here you are using it with > > a user channel which afaik disables the stack processing. > > > > > > > Also, which API allows the user to control the advertising instan= ces you describe? Are they automatically created by the kernel when HCI is= sent to a raw socket to enable advertising? > > > > Nope you need to use the management interface to use the advertising > > instances, or better yet use the D-Bus API: > > > > https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/doc/advertising= -api.txt > > > > > > > Thanks, > > > > > Martin > > > > > > > > > > _____________________________ > > > > > Martin Turon | Google > > > > > > > > > > > > > > > > > > > > On Thu, Dec 13, 2018 at 1:49 PM Luiz Augusto von Dentz wrote: > > > > >> > > > > >> Hi Yunhan, > > > > >> > > > > >> The BlueZ API operates a bit different than HCI, it keeps re-ena= bling the advertisement if there is any instance active, but the user can s= top this by removing its instance once a connection is made, this is consid= ered more convenient than having the user to reprogram the advertisement on= every disconnection. > > > > >> > > > > >> On Thu, 13 Dec 2018, 18:38 Yunhan Wang > > > >>> > > > > >>> +Martin > > > > >>> > > > > >>> Hi, Luiz and Marcel > > > > >>> > > > > >>> When I take a look at the bluetooth code, it seems it is re-ena= bling > > > > >>> ble advertisement after ble connection goes away. Any idea? > > > > >>> > > > > >>> https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluet= ooth.git/tree/net/bluetooth/hci_event.c#n2634 > > > > >>> https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluet= ooth.git/tree/net/bluetooth/hci_event.c#n2712 > > > > >>> https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluet= ooth.git/tree/net/bluetooth/hci_request.c#n1386 > > > > >>> https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluet= ooth.git/tree/net/bluetooth/hci_request.c#n1734 > > > > >>> > > > > >>> Thanks > > > > >>> Best wishes > > > > >>> Yunhan > > > > >>> On Wed, Dec 5, 2018 at 6:54 PM Yunhan Wang wrote: > > > > >>> > > > > > >>> > Hi, Luiz and Marcel > > > > >>> > > > > > >>> > May I have a question on ble behavior on BLE re-advertisement= ? > > > > >>> > > > > > >>> > According to Bluetooth spec Vol. 3 (the host volume), 9.2.4.2= , "The > > > > >>> > device shall remain in general discoverable mode until a conn= ection is > > > > >>> > established or the Host terminates the mode." > > > > >>> > > > > > >>> > There is no description on re-enabling the advertising "after= " > > > > >>> > disconnection, so the responsibility for re-enabling the adve= rtising > > > > >>> > is bluez or kernel or application code? In other words, does = kernel or > > > > >>> > bluez or application would re-enable the ble advertisement af= ter ble > > > > >>> > disconnection happens? > > > > >>> > > > > > >>> > Thanks > > > > >>> > Best wishes > > > > >>> > Yunhan. > > > > > > > > -- > > Luiz Augusto von Dentz --=20 Luiz Augusto von Dentz